#include "mpi.h" int MPI_Attr_put ( comm, keyval, attr_value ) MPI_Comm comm; int keyval; void *attr_value;
The type of the attribute value depends on whether C or Fortran is being used. In C, an attribute value is a pointer (void *); in Fortran, it is a single integer (not a pointer, since Fortran has no pointers and there are systems for which a pointer does not fit in an integer (e.g., any > 32 bit address system that uses 64 bits for Fortran DOUBLE PRECISION).
If an attribute is already present, the delete function (specified when the corresponding keyval was created) will be called.
All MPI objects (e.g., MPI_Datatype, MPI_Comm) are of type INTEGER in Fortran.
All MPI routines (except MPI_Wtime and MPI_Wtick) return an error value; C routines as the value of the function and Fortran routines in the last argument. Before the value is returned, the current MPI error handler is called. By default, this error handler aborts the MPI job. The error handler may be changed with MPI_Errhandler_set; the predefined error handler MPI_ERRORS_RETURN may be used to cause error values to be returned. Note that MPI does not guarentee that an MPI program can continue past an error.